A terminal on a mobile communications network sends and receives a signal by using a terminal antenna. With technical development and application, bandwidth of the terminal antenna needs to cover more frequency bands, that is, the terminal antenna needs to have more resonance points.
However, in pursuit of aesthetics, increasing metal materials are added to an exterior of the terminal, such as an all-metal back cover. For the antenna, the metal materials severely affect the bandwidth, worsen performance, and cause difficulty in design of the terminal antenna. In the prior art, whether in a low-frequency or high-frequency operating state, an antenna of a terminal with a metal back cover can generate a relatively small quantity of resonance points, and bandwidth of the terminal antenna is relatively narrow.